[MSP430F2471] DCO Frequency

Hi Kaka!

Normally you set the DCO frequency to something you want. There are also four calibrated frequencies you can use (1, 8, 12 and 16MHz). Ideally the DCO shall not vary it's frequency dependend on Vcc and temperature, of course, but there might be a slight variation and some initial inaccuracy. TI always gives you the test conditions, like tested at 3V and 25°C. But there is a dependency of Vcc and current consumption, that is why the datasheet gives you more than one test condition, like 1MHz at 2.2V and 3V, for example.

Dennis

Kaka said:

... but TI only define the VCC=2.2V and 3.0V condition ...

Take a look at the data-sheet, it says the DCO frequency fDCO(7,3) is Min 0.8 MHz and Max 1.5 MHz. In other words, one F2471 may have DCO = 0.8 MHz while another may have DCO = 1.5 MHz at the same operating voltage, same temperature and same setting (7,3) -- almost twice as fast.

You asked about wider voltage range and temperature, one chip may have DCO three times faster than another. Will that information be helpful?

You have to calibrate the DCO frequency of the chip individually!